import java.util.Scanner;
    public class Test {
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);
            int n = scanner.nextInt();
            int i;
            for (i = 2;i <= n/2;i++) {
                if(n%i == 0) {
                    System.out.println("n不是素数："+n);
                    break;
                }
            }
            if(i > n/2) {
                System.out.println(n + "是素数");
            }
        }
}
